no screens found(EE) - Cannot use AMD R5 M330 as output to monitor

[Alex Deucher]

On Thu, May 14, 2020 at 1:03 PM Sreyan Chakravarty <sreyan32 at gmail.com> wrote:
>
>
> On 5/14/20 10:17 PM, Alex Deucher wrote:
> > The dGPU on your system has no display hardware.  The displays are
> > only attached to the integrated GPU.
>
> Ok, first of all thanks for the prompt reply, but there is a lot I don't
> understand. I just got into linux in these past 2 months. So please bear
> with me.
>
> If the dGPU has no display attached to it then how is it expected to
> function ? I mean on my desktop I have VGA connected directly to 650 GTX.
>
> How does it work over here ?

There are two GPUs on your system.  One can drives the display and can
render like normal.  The secondary one is just for rendering.  It can
render to an offscreen buffer which them gets copied to the GPU which
drives the displays for display on screen.  There is a bit of overhead
due to the extra copy, but if the dGPU is more substantial you can
still get improved performance relative to rendering on the integrated
GPU.

Alex

>
> >    If you want to use the dGPU for
> > accelerated rendering you will need to use the DRI_PRIME stuff.  E.g.,
> > https://wiki.archlinux.org/index.php/PRIME
> >
> > For example,
> > glxinfo | grep renderer
> > vs.
> > DRI_PRIME=1 glxinfo | grep renderer
> Is the DRI_PRIME set when I select "Launch using dedicated Graphics
> card" in Gnome ?
> >
> > Setting DRI_PRIME will select which GPU is used for OpenGL operations.
> > Modern desktop environments also often have a way to select which GPU
> > the applications run on.
>
> I want all operations to be from the dGPU. You know, my expectation is
> something like that of my desktop I mentioned above. I don't know if
> that is possible.
>
> If not, I would like to understand why it is not possible.
>
> Thanks.
>
> --
> Regards,
> Sreyan
>